In the publication “Adaptive Cruise Control ACC”, published in April, 2002 (ISBN-3-7782-2034-9), the structure of a microwave sensor for distance and speed measurements for automotive applications is described in the chapter “Radar Modules” on pages 10 through 14. There, a high-frequency structure is shown by which transmission signals are forwarded to a patch antenna via a first ring coupler, and the received signals of the patch antenna are forwarded to a second mixer ring via the first ring coupler. The mixer ring also receives the transmit signals of the first ring hybrid, and the mixer ring generates an intermediate-frequency signal from the transmit signal and the receive signal with the aid of two mixer diodes, the intermediate-frequency signal being analyzed by a downstream signal processor for the automatic longitudinal control of a motor vehicle.